The present invention relates to a light hardening device as well as a method for polymerization of polymerizable masses. Light hardening devices of this type are used, for example, if light polymerizable masses or material are to be hardened in a focused manner.
The polymerizable materials which can be hardened by light hardening devices, as is conventionally known, are, for example, cements, an excess amount of which must be applied to complete the application task. The oversupply or excess amount of cement is extremely hard after the complete hardening of the mass or material, and a high degree of effort is required in order to remove this excess material with suitable dental instruments such as, for example, by milling. Moreover, the removal of hardened excess material causes a high wearing away of the scraping or sharpening instruments or, respectively, the milling instruments.
It has been proposed, for example, to use two photo initiators, which have different spectral sensitivity maximums, and to harden the mass or material completely with lamps or lights having the corresponding emission spectrum.
It has further been proposed in the prior art, with respect to photo polymerizable materials which comprise two different photo initiators, to initially activate the first photo initiator by irradiation thereof by an appropriate wavelength so as to thereby partially harden the material, to thereafter remove the excess material, and subsequently, via a second photo initiator, to undertake the complete hardening of the material. Such systems have, however, not found full acceptance due to the considerable effort required to deploy two photo initiators and the switching over work required to switch between the double systems to effect the partial hardening of the material is difficult to control. Therefore, the excess material is typically removed after the complete hardening of the material which requires, however, a considerable effort.